To navigate to the replies to a message, one has to scroll up and down to find the appropriate branch of the tree, which then moves the message just read out of sight.

Ok, let's define "last" and "next".

In a branch, where one posting is an answer to another posting, "last" and "next" is well defined. When I posted an answer, the "last" posting is the one I answered and the "next" is the answer to mine.

OK, there has to be diffentiated between reply (child) and parallel message (sibling). I din't think of siblings, only mother and descendants. But when displaying the links, there should be a clear distinctions between descendants (replies) and siblings (other replies to same "mother").

I linked to the single posting view with the thread tree underneath the posting. The nested view of the postings follows the composition of this thread tree.

Does MLF provide such a "nested view", where the text of a posting is shown right in the tree where it is positioned? At ice-treff.de I can't see a way to select such a view. But, thinking about it, that would be the most logical.

Because

On the other hand in this view one posting follows to the other without need of links.

Same in a hypothetical board view. Is there a possibility to show the thread in a board styled view like in version 1.x? Board view would have a date-of-posting-sorting that could differ from the composition of the threaded and nested views.

That would radically differ. There are other forums, where this is the standard way of doing (like this other forum which I frequent: http://www.bahninfo-forum.de/list.php?9 ), where threads get really uncomprehensible when reply to relatively old messages are being posted.

All in all (after discussion about the details) a good idea.

I'm looking forward to see it